This invention relates to non-reusable aspirating safety syringes with retractable needles for use, for example, in the dental, medical or veterinary arts.
Disposable syringes with retractable needles are desirable because they are economical and hygienic. Retractable needles are especially desirable because they greatly reduce accidental sticking of needles in caregivers and patients. Further, the retractable nature of needles is desirable because they provide a visual aid indicating prior use. In addition, many retractable designs make reuse of the needle and syringe impossible.
Of particular importance in the dental arts is a syringe that may be used to aspirate. Aspiration is the practice of retracting a syringe plunger in order to draw fluids from the patient""s body into the drug cartridge so that the caregiver may verify whether a vein was mistakenly invaded. The desirable characteristics of aspirating syringes and other necessary functions are extolled in U.S. Pat. No. 6,068,618 and incorporated herein by reference.
However, in the dental arts, for example, medication and anesthetic are often consumed in disposable vials or cartridges. The prior art describes re-usable syringes that are adapted to receive such single use, disposable cartridges. But, there are inherent drawbacks to this method of consuming dental drugs.
First, traditional disposable syringes are generally inexpensive and simple in design. Further, some can retract a needle after use, thus facilitating proper disposal. But, they cannot accommodate common single use disposable drug cartridges.
To overcome some of these drawbacks, a re-usable syringe was developed. Constructed of a durable material, such as chrome plated brass or stainless steel, such syringes readily accepted the disposable cartridges and the syringes were adapted for use as aspirating syringesxe2x80x94having a modified plunger with a handle feature that facilitated both dispensing drugs and aspiration. Although this type of syringe is very successful, it too has drawbacks. For example, the durable construction from brass or stainless steel is costly. Second, the re-use of the syringe necessitates a relatively expensive sterilization procedure and additional equipment. Further, the re-useable syringe is susceptible to re-use prior to proper sterilization, which may promote the spread of germs, viruses and other contagious diseases.
In addition, the avoidance of needle sticks (that is the in advertent pricking of a patient or caregiver with a needle) when using re-useable syringe assemblies is not adequately addressed in the prior art, because many of such previous devices do not have the ability to retract a needle after use. In the current designs of most re-usable syringe assemblies, the needle must be removed by hand. This greatly increases the risk of an accidental needle stick.
It is therefore desirable to have a novel disposable syringe that incorporates the advantages of an economical syringe and the safety features of a retractable needle, with such characteristics as captured in reusable syringes, such as the ability to aspirate and accommodate disposable cartridges.
Generally, the novel syringe features a retractable needle. The syringe includes a plunger, a barrel and a body. The body is, for example, generally tubular and hollow and has a longitudinal opening. On the exterior of the body at a proximal end, there is a finger grip feature, which is known in the art. This feature is for the comfort and convenience of the caregiver, and the syringe would work in substantially the same manner with or without such a contoured finger grip. The syringe body may also include a handle at the proximal end. This feature could assist with aspiration and control of the syringe. At the oppositely spaced distal end of the body is a nozzle feature. The nozzle feature is adapted to receive the barrel assembly.
As mentioned, the body has a longitudinal opening. The longitudinal opening easily accepts a disposable cartridge of fluid drug, as known in the art. However, a cartridge may be successfully introduced to the syringe body by placing the cartridge in either a proximal or distal open end, in the alternative.
In lieu of a known cartridge, an alternative novel capsule may be used, as described subsequently. In either instance, the cartridge or the novel capsule may be inserted in the longitudinal opening, or introduced at one open end of the body. Once positioned, the cartridge or capsule is engaged by the plunger at one end and the barrel at a second end, for example. The barrel is adapted to pierce a flexible membrane or diaphragm of the capsule or cartridge.
The barrel has a feature that protrudes from a central body. The protrusion has a barb. The barb and protrusion are hollow, allowing fluid communication between the capsule or cartridge and the barrel assembly.
At an end opposite from the barbed protrusion is a threaded member, for example, that is adapted to receive a needle assembly, as known in the art. It is contemplated and within the scope of the present invention for the needle assembly to attach with a LUER(copyright) lock or any other locking mechanism. The needle assembly may be a double piercing needle, as typically used with re-useable syringe assemblies of the prior art. Alternatively, the needle assembly may be a single piercing construction as is common with known disposable, single use needles.
Also included with the barrel is a seal. The seal rests around a peripheral surface and is in sealing contact with the nozzle of the syringe body. For example, an o-ring may be used to removably seal the barrel and the body.
The nozzle of the syringe body has a feature that retains the barrel in fixed position, preventing the barrel from being dislodged from the distal end, but permitting the barrel and needle assemblies to be retracted after use and withdrawn toward the plunger end of the syringe body, and drawn entirely within the capsule.
The syringe assembly also has a plunger that is slidebly received in the hollow tubular body. The plunger has a feature that engages the top plug of the drug cartridge or capsule. The plunger may also include a looped member, as is used in the art to facilitate the use of the needle to aspirate. The plunger also has a breakaway feature, for example, a score line, so that a used plunger may be fractured after use. This will allow a more compact disposal of the invention.
As mentioned, a known disposable fluid drug cartridge may be used with this novel syringe. In such a case, a double piercing needle may be attached to the barrel assembly. One end of the needle would pass through the barrel and the barbed protrusion would pierce the cartridge diaphragm. After use, the double piercing needle would be unscrewed from the barrel. Then the syringe assembly and cartridge would be discarded normally. Alternately, a single piercing needle may be used. It would be attached to the barrel assembly. After use, the entire barrel along with the needle would be withdrawn and captured entirely within the capsule.
Therefore, the present invention alleviates many of the aforementioned deficiencies in the prior art. Insodoing, it is therefore one object of the invention to provide an aspirating safety syringe with a retractable needle. Moreover, it is an object of the present invention to provide a disposable aspirating syringe.
It is a further object of the invention to provide a syringe that can receive disposable, single use drug cartridges.
It is another object to provide such a disposable syringe that is economical to manufacture and dispose.
Another object of the invention is to increase safety by providing a visual means to indicate that a syringe has been used and also to reduce the probability of inadvertent needle xe2x80x9csticks.xe2x80x9d
Yet another object of the invention is to provide a novel disposable cartridge for drugs that can be used with the novel disposable aspirating syringe.